20th Century Technology

Personal Computer
Early computers were bulky, tube-powered behemoths. But with the development of the microprocessor by Intel in 1971, computers became smaller, easier to use and increasingly affordable. Combined with user-friendly operating systems such as Microsoft's Windows or Apple's operating system, the PC has become a dominant tool in the global economy and a mainstay appliance in a growing number of homes.

• The Voting Machines of America